Meta-Analysis of the Effects of Parent Effectiveness Training

There have been two extensive reviews of P.E.T. course evaluation studies.

"The first, by Ronald Levant of Boston University, reviewed 23 different studies (1983). The author concluded that many of the studies had methodological discrepancies. Nevertheless, out of a total of 149 comparisons between P.E.T. and control groups or alternative programs, 32% favored P.E.T., 11% favored the alternative group, and 57% found no significant differences. Levant did find three studies that met the standards of methodological adequacy. In these studies, out of 35 comparisons, 69% favored P.E.T. over the control group, none (0%) favored the control group, and 31% showed no significant differences. Levant concluded that P.E.T. appears to result in positive changes in parent attitudes and behavior and changes in children’s self-concept and behavior.

Robert Cedar of Boston University later reviewed 26 of the best designed research studies of P.E.T., using the “meta-analytic technique” of integrating the statistical findings from all the studies (1987).

His findings:

  • The overall positive effect of P.E.T. was significantly greater than the effect of alternative treatments,
  • The greatest measurable effect was on parent attitudes,
  • The effect of P.E.T. on parent behavior was significantly greater than the effect of alternative groups,
  • P.E.T.’s effect on children was greatest for the category of self-esteem,
  • Parents did learn the P.E.T. concepts,
  • P.E.T. parents improved their attitudes, showed greater understanding of children, increased their democratic ideals, showed increased positive regard, empathy, congruence, and respect for their children,
  • P.E.T. children rated their parents as more accepting of their children,
  • The positive effects of P.E.T. last longer than the eight weeks training. In fact, they lasted as long as a 26-week follow-up,
  • P.E.T.’s positive effect on children increased over time,
  • The magnitude of the positive effects of P.E.T. was greatest in those studies that had superior research methodology."

Taken from 'P.E.T. Research' on the Gordon Training International website. There are other relevant research findings also listed there.

'A meta-analysis of the effects of parent effectiveness training' by Bruce Cedar and Ronald F. Levant was published online in the American Journal of Family Therapy on 05 Oct 2010. The findings were:

The results of this meta-analytic study showed PET to have an overall effect size of 0.33 standard deviation units, which was significantly greater than the effect size of a group representing alternative treatments. PET has effects on parents' knowledge, attitudes, and behavior and on children's self-esteem, and these effects endured (up to 26 weeks) after the programs were completed. There was a trend suggesting that the effect on child behavior may have a latency period. Better designed studies were found to have significantly greater effect sizes (.45) than less well-designed studies (.26).